title: Protein F, a fibronectin-binding protein of Streptococcus pyogenes, also binds human fibrinogen: isolation of the protein and mapping of the binding region.
abstract: During screening of a gene library of Streptococcus pyogenes type M15 for fibrinogen-binding material, a protein of approximately 100 kDa, encoded outside the vir region, was found. DNA sequencing revealed this component to be identical to protein F, a fibronectin-binding protein. Isolation of the recombinant protein, termed F15, was performed by the use of fibrinogen affinity chromatography. The affinity constant (Ka) of protein F15 for fibrinogen, 1.25 x 10(7) mol-1, was lower than that for fibronectin, 1.8 x 10(8) mol-1. The fibrinogen-binding domain was located in the N-terminal part of the molecule, while the fibronectin-binding domains, as previously determined, were in the C-terminal portion of protein F. To examine the amino acid sequence heterogeneity of protein F, the 5' part of the prtF gene, corresponding to the N-terminal variable region of the protein, was amplified by PCR from 12 strains of S. pyogenes belonging to six different M-types. Alignment of these nucleotide sequences indicated that the 5' portion of the prtF gene had probably undergone a number of intragenic recombination and horizontal gene transfer events, allowing a pattern of structural diversity of protein F observed earlier for some other streptococcal virulence factors. There was no strict correlation between M-type and nucleotide sequence of the variable region of the prtF gene and, compared to streptococcal M protein, the overall variation observed for protein F appeared more limited.
authors.affiliation: Department of Medical Microbiology, University of Lund, Sölvegatan 23, S-22362 Lund, Sweden.|Institute of Experimental Medicine, Academy of the Medical Sciences, St Petersburg, Russia.
authors.forename: Viacheslav
authors.initials: V
authors.lastname: Katerov
authors.affiliation: Institute of Experimental Medicine, Academy of the Medical Sciences, St Petersburg, Russia.
authors.forename: Andrej
authors.initials: A
authors.lastname: Andreev
authors.affiliation: Department of Medical Microbiology, University of Lund, Sölvegatan 23, S-22362 Lund, Sweden.
authors.forename: Claes
authors.initials: C
authors.lastname: Schalén
authors.affiliation: Institute of Experimental Medicine, Academy of the Medical Sciences, St Petersburg, Russia.
authors.forename: Artem A
authors.initials: AA
authors.lastname: Totolian
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D017931:DNA Primers; D005340:Fibrinogen / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D015723:Gene Library; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D013297:Streptococcus pyogenes / Q000235:genetics / Q000502:physiology*
chemical_list: D018829:Adhesins, Bacterial; D017931:DNA Primers; D005353:Fibronectins; D011994:Recombinant Proteins; C078635:fibronectin-binding proteins, bacterial; D005340:Fibrinogen